Optical adaptive lens and endoscope

Abstract

The utility model relates to an optical adaptive lens and an endoscope. The optical adaptive lens sequentially comprises a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power and a fourth lens with negative focal power from an object side to an image side along an optical axis, the first cemented lens group has negative focal power, the first cemented lens group comprises a second lens and a third lens which are cemented and are sequentially arranged from the object side to the image side along the optical axis, and the object side surface of the second lens is a convex surface; the second cemented lens group has positive focal power, the second cemented lens group comprises a fourth lens and a fifth lens which are cemented and are sequentially arranged from the object side to the image side along the optical axis, and the object side surface of the fourth lens is a concave surface; and the sixth lens has negative focal power, and the image side surface of the sixth lens is a concave surface. According to the optical adaptive lens, various aberrations such as chromatic aberration and distortion can be corrected, the imaging resolution and the image detail sharpness can be improved, and the size of the optical adaptive lens can be compressed.

Description

Technical Field

[0001] This application relates to the field of endoscope technology, and in particular to an optical adapter lens and an endoscope. Background Technology

[0002] An endoscope is a medical device that can be inserted into the human body for observation, diagnosis, or treatment. An endoscope typically includes an image sensor, an optical adapter lens, and an endoscope mirror. The endoscope mirror is inserted into the human body to collect images, and the images collected by the endoscope mirror can be adjusted and transmitted to the image sensor through the optical adapter lens.

[0003] Among these factors, the imaging quality of the optical adapter lens is a crucial factor in the overall imaging quality of the endoscope, significantly impacting the accuracy of diagnosis and treatment. The size of the optical adapter lens also affects the user's experience during extended use. However, current optical adapter lenses struggle to balance good imaging quality with miniaturized design. Utility Model Content

[0004] Therefore, it is necessary to provide an optical adapter lens and endoscope to address the current problem that optical adapter lenses cannot simultaneously achieve good image quality and miniaturization.

[0005] An optical adapter lens, comprising, along the optical axis from the object side to the image side, the following components in sequence:

[0006] A first lens having positive optical power, wherein the object side of the first lens is convex;

[0007] A first cemented lens assembly with negative optical power, the first cemented lens assembly including a second lens and a third lens cemented together and arranged sequentially from the object side to the image side along the optical axis, the object side of the second lens being convex;

[0008] A second cemented lens assembly with positive optical power, the second cemented lens assembly including a fourth lens and a fifth lens cemented together and arranged sequentially from the object side to the image side along the optical axis, wherein the object side of the fourth lens is concave;

[0009] A sixth lens with negative optical power, wherein the image-side surface of the sixth lens is concave.

[0010] The aforementioned optical adapter lenses feature rationally designed optical power and surface shape for each lens. Combined with the design of the cemented lens assembly, this facilitates the correction of various aberrations such as chromatic aberration and distortion, improving imaging resolution and image detail sharpness. Consequently, it enhances the imaging quality of the optical adapter lenses, which is beneficial for improving the accuracy of diagnosis and treatment when used in endoscopes. It also helps to reduce the size of the optical adapter lenses, making it easier for users to operate and hold the endoscope for extended periods. This achieves a balance between good imaging quality and miniaturized design.

[0011] In one embodiment, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has negative optical power, and the fifth lens has positive optical power.

[0012] In one embodiment, the image-side surface of the second lens is convex, the object-side surface of the third lens is concave, the image-side surface of the fifth lens is convex, and the object-side surface of the sixth lens is convex.

[0013] In one embodiment, the optical adapter lens satisfies the following condition:

[0014] 1.5≤f2 / (f2-f3)≤1.8;

[0015] Where f2 is the focal length of the first lens and f3 is the focal length of the first cemented lens group.

[0016] In one embodiment, the optical adapter lens satisfies the following condition:

[0017] 7.5≤f2 / (f2-f4)≤8.5;

[0018] Where f2 is the focal length of the first lens and f4 is the focal length of the second cemented lens group.

[0019] In one embodiment, the optical adapter lens satisfies the following condition:

[0020] 0.05≤|CT4 / f4|≤0.085;

[0021] Wherein, CT4 is the thickness of the second cemented lens group on the optical axis, and f4 is the focal length of the second cemented lens group.

[0022] In one embodiment, the optical adapter lens further includes a lens protection element disposed on the object side of the first lens, and the optical adapter lens satisfies the following condition:

[0023] 0.2≤CT2 / (T12+T23)≤0.6;

[0024] Wherein, CT2 is the thickness of the first lens on the optical axis, T12 is the distance on the optical axis from the image side of the lens protection element to the object side of the first lens, and T23 is the distance on the optical axis from the image side of the first lens to the object side of the first cemented lens assembly.

[0025] In one embodiment, the optical adapter lens satisfies the following condition:

[0026] 1.5°≤Semi-FOV≤7.5°;

[0027] 20mm≤f≤35mm;

[0028] Wherein, Semi-FOV is half of the maximum field of view of the optical adapter lens, and f is the focal length of the optical adapter lens.

[0029] In one embodiment, the optical adapter lens further includes an aperture stop disposed on the object side of the first lens.

[0030] An endoscope comprising an optical adapter lens as described in any of the above embodiments. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the optical adapter lens in some embodiments.

[0032] Figure 2 This is a transfer function graph of the optical adapter lens in some embodiments.

[0033] Figure 3 This is a defocus curve diagram of the optical adapter lens in some embodiments.

[0034] Figure 4 This is a dot diagram of the optical adapter lens in some embodiments.

[0035] Figure 5 The diagram shows the field curvature and distortion curves of the optical adapter lens in some embodiments.

[0036] Figure label:

[0037] 10. Optical adapter lens; E1. Lens protection element; S3. Aperture stop; E2. First lens; E3. First cemented lens group; E31. Second lens; E32. Third lens; E4. Second cemented lens group; E41. Fourth lens; E42. Fifth lens; E5. Sixth lens; S14. Imaging plane. Detailed Implementation

[0038] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0039] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0041] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0042] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0043] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0044] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an optical adapter lens in some embodiments. The optical adapter lens provided in this application can be used in medical devices, such as endoscopes. In some embodiments, the endoscope may further include an endoscope mirror and an image sensor. The optical adapter lens is disposed in the endoscope mirror and the image sensor. The endoscope mirror can at least partially extend into the human body to acquire images of lesion areas. The light acquired by the endoscope mirror can be adjusted and transmitted by the optical adapter lens and then projected onto the image sensor. The optical adapter lens plays a connecting and adapting role between the endoscope mirror and the image sensor to improve the imaging quality of the endoscope. In some embodiments, in the endoscope, the optical adapter lens can also be combined with any suitable driving mechanism such as a voice coil motor to achieve automatic focusing by driving the lenses in the optical adapter lens to move synchronously along the optical axis.

[0045] Furthermore, in some embodiments, the optical adapter lens comprises six lenses with optical power. The optical adapter lens, along the optical axis from the object side to the image side, sequentially includes a first lens E2, a first cemented lens group E3, a second cemented lens group E4, and a sixth lens E5. The first cemented lens group E3 includes a second and a third lens cemented together and sequentially arranged along the optical axis from the object side to the image side. The second cemented lens group E4 includes a fourth and a fifth lens cemented together and sequentially arranged along the optical axis from the object side to the image side. The optical adapter lens has an imaging surface S14. When the optical adapter lens is installed in an endoscope, the imaging surface S14 can at least partially overlap with the photosensitive surface of the image sensor. Light from the object side can be directed onto the imaging surface S14 after being adjusted sequentially by each lens in the optical adapter lens.

[0046] The first lens E2 has positive optical power, and its object-side surface is convex. The first cemented lens group E3 has negative optical power, meaning the combined optical power of the second and third lenses is negative. The object-side surface of the first cemented lens group E3 is convex, meaning the object-side surface of the second lens is also convex. The second cemented lens group E4 has positive optical power, meaning the combined optical power of the fourth and fifth lenses is positive. The object-side surface of the second cemented lens group E4 is concave, meaning the object-side surface of the fourth lens is also concave. The sixth lens E5 has negative optical power, and its object-side surface is concave.

[0047] The aforementioned optical adapter lenses feature rationally designed optical power and surface shape for each lens. Combined with the design of the cemented lens assembly, this facilitates the correction of various aberrations such as chromatic aberration and distortion, improving imaging resolution and image detail sharpness. Consequently, it enhances the imaging quality of the optical adapter lenses, which is beneficial for improving the accuracy of diagnosis and treatment when used in endoscopes. It also helps to reduce the size of the optical adapter lenses, making it easier for users to operate and hold the endoscope for extended periods. This achieves a balance between good imaging quality and miniaturized design.

[0048] Specifically, the optical power and surface design of the first lens E2 enable it to effectively deflect light, facilitating the capture of more light and improving the relative illumination of the image. The optical power and surface design of the first cemented lens group E3, in conjunction with the first lens E2, effectively control the direction and divergence of light, improving the structural compactness of the optical adapter lens and thus reducing its axial dimensions. The optical power and surface design of the second cemented lens group E4 effectively guide light, ensuring a smooth transition and reducing tolerance and aberration sensitivity. This improves the molding and assembly yield of each lens and also reduces the risk of ghosting, enhancing the image quality of the optical adapter lens. The optical power and surface design of the sixth lens E5, in conjunction with the other lenses, effectively diverges light onto the imaging surface S14, improving the matching degree between the incident angle of light on the imaging surface S14 and the image sensor, while also meeting image height requirements, thus improving the relative illumination and resolution of the image. The bonding design of the first cemented lens group E3 and the second cemented lens group E4 also helps to balance the chromatic aberration of the optical adapter lens, further improving the imaging quality of the optical adapter lens.

[0049] In some embodiments, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has negative optical power, and the fifth lens has positive optical power. The image-side surface of the first lens E2 is flat, the image-side surface of the second lens is convex, the object-side surface of the third lens is concave, and the image-side surface is flat. The image-side surface of the fourth lens and the object-side surface of the fifth lens are flat, the image-side surface of the fifth lens is convex, and the object-side surface of the sixth lens E5 is convex. Therefore, by combining the optical power and surface shape of the above lenses, the direction of light can be reasonably controlled, which is beneficial for correcting various aberrations such as distortion and chromatic aberration, reducing the tolerance sensitivity and aberration sensitivity of the optical adapter lens, and improving the structural compactness of the optical adapter lens, thus achieving both good image quality and miniaturized design.

[0050] In some embodiments, the optical adapter lens further includes an aperture stop S3, which is located on the object side of the first lens E2. The front-positioned design of the aperture stop S3, combined with the optical power and surface shape design of each lens in the optical adapter lens, helps to improve the structural compactness of the optical adapter lens, thereby further reducing the axial dimensions of the optical adapter lens and facilitating long-term operation and handling of the endoscope by the user. In some embodiments, the optical adapter lens further includes a lens protection element E1, which is located on the object side of the first lens E2. The lens protection element E1 includes, but is not limited to, flat glass, used to protect each lens in the optical adapter lens. In some embodiments, the material of each lens in the optical adapter lens includes, but is not limited to, any suitable glass or plastic. Using common and readily available materials helps to reduce processing difficulty and manufacturing costs.

[0051] In some embodiments, the optical adapter lens satisfies the following conditions: 1.5° ≤ Semi-FOV ≤ 7.5°; 25mm ≤ f ≤ 30mm; where Semi-FOV is half of the maximum field of view of the optical adapter lens, and f is the focal length of the optical adapter lens. For example, Semi-FOV can be 1.5, 2, 3, 4, 5.5, 6, or 7.5, in degrees, and f can be 25, 26, 27, 28, 29, or 30, in millimeters. When the above conditions are met, the field of view and imaging quality of the optical adapter lens can be balanced by the optical power and surface design of each lens. This achieves good imaging quality while meeting the imaging requirements of the endoscope, thereby improving the accuracy of diagnosis and treatment.

[0052] In some embodiments, the optical adapter lens satisfies the condition: 1.5 ≤ f2 / (f2-f3) ≤ 1.8; where f2 is the focal length of the first lens E2, and f3 is the focal length of the first cemented lens group E3, i.e., the combined focal length of the second and third lenses. For example, f2 / (f2-f3) can be 1.5, 1.6, 1.7, or 1.8. When the above condition is satisfied, the optical interaction between the first lens E2 and the first cemented lens group E3 can be reasonably configured, thereby reasonably controlling the light path of the first lens E2 and the first cemented lens group E3, which is beneficial for suppressing aberrations such as chromatic aberration, spherical aberration, coma, and astigmatism, and improving image sharpness and image quality.

[0053] In some embodiments, the optical adapter lens satisfies the condition: 7.5 ≤ f2 / (f2-f4) ≤ 8.5; where f2 is the focal length of the first lens E2, and f4 is the focal length of the second cemented lens group E4, i.e., the combined focal length of the fourth and fifth lenses. For example, f2 / (f2-f4) can be 7.5, 7.7, 7.8, 7.9, 8, 8.2, 8.4, or 8.5. Satisfying the above condition helps to balance the optical power distribution of the optical adapter lens, corrects aberrations such as spherical aberration and chromatic aberration, and improves the imaging quality of the optical adapter lens.

[0054] In some embodiments, the optical adapter lens satisfies the condition: 0.05 ≤ |CT4 / f4| ≤ 0.085; where CT4 is the thickness of the second cemented lens group E4 on the optical axis, i.e., the distance on the optical axis from the object side of the fourth lens to the image side of the fifth lens, and f4 is the focal length of the second cemented lens group E4, i.e., the combined focal length of the fourth and fifth lenses. For example, |CT4 / f4| can be 0.05, 0.06, 0.07, 0.078, 0.08, or 0.085. Satisfying the above condition balances the mechanical stability and optical performance of the second cemented lens group E4, which is beneficial for improving the structural reliability of the second cemented lens group E4, as well as for correcting aberrations such as field curvature, thereby improving the imaging quality of the optical adapter lens.

[0055] In some embodiments, the optical adapter lens satisfies the condition: 0.2 ≤ CT2 / (T12+T23) ≤ 0.6; where CT2 is the thickness of the first lens E2 on the optical axis, T12 is the distance on the optical axis from the image-side surface of the lens protection element E1 to the object-side surface of the first lens E2, and T23 is the distance on the optical axis from the image-side surface of the first lens E2 to the object-side surface of the first cemented lens group E3 (i.e., the object-side surface of the second lens). For example, CT2 / (T12+T23) is 0.2, 0.3, 0.4, 0.5, or 0.6. When the above condition is satisfied, the relative position and size of the first lens E2 in the optical adapter lens can be reasonably configured, which is beneficial for reasonably controlling the degree of light refraction of the first lens E2, suppressing aberrations such as distortion and coma, and also improving the structural compactness of the optical adapter lens and reducing its axial dimensions.

[0056] Please see Figures 2-5 As shown, Figure 2 This is a plot of the MTF (Mean Transfer Function) of the optical adapter lens in some embodiments. Figure 3 This is a defocus curve diagram of the optical adapter lens in some embodiments. Figure 4 This is a dot diagram of the optical adapter lens in some embodiments. Figure 5 These are field curvature and distortion curves for the optical adapter lens in some embodiments. Figures 2-5As can be seen, in some embodiments, when the resolution of the optical adapter lens meets 200 lp / mm, the MTF value across the entire field of view is greater than 0.25 and close to the diffraction limit, the maximum root mean square radius in the dot plot is 2.208, and the distortion across the entire field of view is within 2.5%. Therefore, the optical adapter lens possesses good image quality, balancing clear imaging with small size requirements, meeting the needs of 4K optical mounts, and is compatible with 4K camera systems.

[0057] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An optical adapter lens, characterized in that, Along the optical axis from the object side to the image side, the following are included in sequence: A first lens having positive optical power, wherein the object side of the first lens is convex; A first cemented lens assembly with negative optical power, the first cemented lens assembly including a second lens and a third lens cemented together and arranged sequentially from the object side to the image side along the optical axis, the object side of the second lens being convex; A second cemented lens assembly with positive optical power, the second cemented lens assembly including a fourth lens and a fifth lens cemented together and arranged sequentially from the object side to the image side along the optical axis, wherein the object side of the fourth lens is concave; A sixth lens with negative optical power, wherein the image-side surface of the sixth lens is concave.

2. The optical adapter lens according to claim 1, characterized in that, The second lens has positive optical power, the third lens has negative optical power, the fourth lens has negative optical power, and the fifth lens has positive optical power.

3. The optical adapter lens according to claim 2, characterized in that, The image-side surface of the second lens is convex, the object-side surface of the third lens is concave, the image-side surface of the fifth lens is convex, and the object-side surface of the sixth lens is convex.

4. The optical adapter lens according to claim 1, characterized in that, The optical adapter lens satisfies the following condition: 1.5≤f2 / (f2-f3)≤1.8; Where f2 is the focal length of the first lens and f3 is the focal length of the first cemented lens group.

5. The optical adapter lens according to claim 1, characterized in that, The optical adapter lens satisfies the following condition: 7.5≤f2 / (f2-f4)≤8.5; Where f2 is the focal length of the first lens and f4 is the focal length of the second cemented lens group.

6. The optical adapter lens according to claim 1, characterized in that, The optical adapter lens satisfies the following condition: 0.05≤|CT4 / f4|≤0.085; Wherein, CT4 is the thickness of the second cemented lens group on the optical axis, and f4 is the focal length of the second cemented lens group.

7. The optical adapter lens according to claim 1, characterized in that, The optical adapter lens further includes a lens protection element, which is disposed on the object side of the first lens. The optical adapter lens satisfies the following condition: 0.2≤CT2 / (T12+T23)≤0.6; Wherein, CT2 is the thickness of the first lens on the optical axis, T12 is the distance on the optical axis from the image side of the lens protection element to the object side of the first lens, and T23 is the distance on the optical axis from the image side of the first lens to the object side of the first cemented lens assembly.

8. The optical adapter lens according to any one of claims 1-7, characterized in that, The optical adapter lens satisfies the following condition: 1.5°≤Semi-FOV≤7.5°; 20mm≤f≤35mm; Wherein, Semi-FOV is half of the maximum field of view of the optical adapter lens, and f is the focal length of the optical adapter lens.

9. The optical adapter lens according to any one of claims 1-7, characterized in that, The optical adapter lens also includes an aperture stop, which is located on the object side of the first lens.

10. An endoscope, characterized in that, Including the optical adapter lens as described in any one of claims 1-9.

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